Apparatus for molding foam articles

ABSTRACT

This disclosure relates to a molding apparatus having a mold support means with molds positioned thereon and means above the molds to permit a mixing head to move above the molds and having flexible connections to the foamable ingredient&#39;&#39;s supply system.

United States Patent Inventors Dale J. Meyers; [56] James E. Ditty, bothof Logan, Ohio Appl. No. 812,692

Filed Apr. 2, 1969 2 12%;

Patented Aug. 17, 1971 3249486 Assignee The Goodyear Tire 8: RubberCompany H3 Akron, Ohio APPARATUS FOR MOLDING FOAM ARTICLES 3 Claims, 4Drawing Figs.

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Field oiSearch B, 5 P, 1 M, 5 M,26 M;2S/1 M; 141/232, 233;

References Cited UNITED STATES PATENTS 3/1891 Howard 18/26MX 6/1948Leguillon et a1. 18/30 PS 5/1966 Voisinetet al..... 18/5 P 6/1969 Maizel141/232 FOREIGN PATENTS 4/1920 Norway 141/232 Primary Examiner.l.Spencer Overholser Assistant Examiner- Lucius R. Frye Attorneys-J. W.Brunner and J. D. Wolfe 18/5 P, 264/54 B29c 3/04 ABSTRACT: Thisdisclosure relates to a molding apparatus having a mold support meanswith molds positioned thereon and means above the molds to permit amixing head to move above the molds and having flexible connections tothe foamable ingredient's supply system.

PATENTEU AUG] 7 I971 FIG. 2

ATTORNEY PATENTEDAUMYIHTI 3.599.282

SHEET 3 U? 3 BY DALE J. MEYERS FIG. 4

APPARATUS FOR MOLDING FOAM ARTICLES This invention relates to anapparatus capable of pouring a foamable mixture into molds positioned ina desired pattern on a pouring floor.

In the molding of foamed articleshaving a skin that has been preformedit is necessary that the mold be of sufficient strength to maintain thepreformed skin in the desired configuration while the foam is expandingwithin the cavity of the preformed skin. Likewise, in molding anyfoamable material it is required that the mold be of sufficient strengthto withstand any pressure developed during the molding operation.Consequently, the molds used in molding foamed articles tend to berelatively large and bulky and difficult to move. Therefore, it has beenfound desirable to provide apparatus that can be moved to the mold topour the mold and thus keep the time between the actual mixing andformation of the foamable reaction mixture and its addition to the moldto essentially a minimum to avoid the difiiculties inherent in the useor pouring of a foamable mixture which is relatively aged.

Therefore, an object of this invention is to provide an apparatuswhereby the molds may be positioned on or about the pouring floor andthe pouring head or means can be moved from one mold to the next toachieve pouring of the foamable mixture into the mold without thefoamable mixture being appreciably aged. 1

This object and other advantages of this method of molding foamedarticles can be more readily appreciated by reference to the drawingswherein:

FIG. 1 is a planned view of the molding apparatus; and

FIG. 2 is an elevational view along the lines 2-2 of FIG. 1;

FIG. 3 is an elevational sectional view along the lines 3-3 of FIG. 1showing the convolute flexible line arrangement for connecting themixing head to the feed pump from the ingredient storage tanks; and

FIG. 4 is a partial sectional view in elevation of the apparatus showinga tilting mold.

Referring to the drawings, numeral 3 represents a double track suspendedabove a pouring platform 4 with the track 3 being preferably an arc of acircle to reduce the distance traveled by the pouring head and to permitthe pouring head 5 to be located relatively close to the central storagetanks 6. It is desired that the track be either a semicircle (arc of acircle or ellipse) or U-shaped to obtain these desired features.

Referring again to FIG. 1 it will be noted that within the foamableingredients storing area 6 there are a series of tanks 7 which containthe foamable ingredients which may have heaters (not shown) foradjusting the temperature of the ingredients, for instance, to above themelt temperature of said ingredient. Associated with each of these tanksis a pump 8. A line 9 extends from each tank to a pump 8 and from thepump 8 to the pouring head 5. Also associated with each feed line, wheredesired, is a recycle line from the pouring or mixing head valve to eachspecific ingredient storage tank. Lines 9 include a series of flexiblelines 10 that are suspended overhead in convolute curves 11 or loops 11to permit the pouring head to be moved on the tracks 3 by causing thewheels 12 associated with the carriage 13 for the pouring head 5 to movein the desired direction. The movement of the pouring head and itsassociated carriage is achieved preferably by applying push or pull withthe hand on the hand member 14 of the pouring head. Thus, by applyingsuitable push or pull the pouring head can be moved from the stop 15through various intermediate positions around the track to the stop 14or returned from the stop 14 through various intermediate stops to stop16. To operate this apparatus the molds 17 are placed on the flooressentially under the track 3, preferably in a semicircle or U-shapedarrangement as shown best in FIG. 1. Where the mold is to be used toform a foamed article without preformed skin the mold is opened andcoated with a mold release agent such as a polyethylene or wax. Then thepouring head is moved over the mold and the operating means, i.e., the

start button 18 in the electric circuit with the pump motors and thesolenoid valve in the feed lines to the mixing head is activated tocause the mold to receive the desired amount or load of foamablemixture. As soon as thecharge or load of foamable mixture has been addedto the mold the solenoid valve mechanism 20 associated with the pouringhead 5 is closed by hand activation of the switch 21 in the panel board19 associated with the pouring head. It is preferred that the activationof start button 18 also start a timer that activates switch 21 onexpiration of the set time to stop the pour. When the pour is stopped,the pouring head is then moved to the next mold, preferably a successiveone, where another charge of a foamable reaction mixture is added to amold. As soon as the pouring head is moved from over the last pouredmold, that mold is closed and the lid preferably is fastened although insome instances the lid may be allowed to float upward in accordance withthe well-known floating lid technique.

It should be noted that as the pouring head moves around the track 3flexible pipe hangers 22 must move back and forth on wheels 24 in theflexible pipe trackway 23. It should also be noted that as the pipehangers move apart along the trackway the shape of the convolute curesof the flexible pipe or hose changes to permit the pouring head to movealong the track to either increase or decrease the distance from thepouring head to the storage tanks 7.

Where the foamed article to be manufactured has a preformed skin, it canbe made by hot melt molding techniques for the thermoplastic resins orpolymers or by vacuum forming the skin from a warm film of athermoplastic resin.

Representative of the many thermoplastic resins or polymers that may beemployed in the present invention to cast or form the skin are vinylpolymers preferably in the highviscosity range. Preferred among thelatter are the polymers of vinyl chloride, vinyl acetate, vinyl butyral,and copolymers of vinyl chloride and vinyl acetate. A copolymer whichhas proven satisfactory is one prepared from 93 to 95 percent vinylchloride and the balance vinyl acetate, with an average molecular weightof approximately 24,000 as determined by the Staudinger method, andhaving a specific gravity of about [.34 to L37, and softening atapproximately F. These above-mentioned polymer materials, when formedfor present purposes, require no chemical or other treatment except theaddition of a plasticizer. Also, the thermoplastic ABS resinacrylonitrile-butadiene-styrene polymer) can be used to form the skin.Plasticizers are employed which are compatible with these polymers, andwhich contain no constituents that are, as in the case of the polymers,reactive with atmospheric oxygen in the range of atmospherictemperatures. Examples of such plasticizers are tricresyl phosphate,dioctyl phthalate, dicapryl phthalate, dibutyl sebacate, dibutoxy ethylphthalate, dibutoxyglycol phthalate, polyethyleneglycol di-2-ethylhexoate, triethylene-glycol-di-2-ethyl hexoate and the like.

A representative example of how this invention can be practiced is shownbelow with all parts being by weight unless otherwise indicated.

EXAMPLE I ing or retaining mold located on the floor as shown in FIG. I.

Then suflicient polyurethane foamable mixture was added from the pouringhead which had been moved above the mold to fill the mold when foamingwas complete. Then the mixing head was moved to the next mold, the moldwas closed and the mold was opened and the mold.

A polyether urethane foamable reaction mixture used to form the crashpad in example I was prepared by mixing about 94.0 equivalents of apolypropylene ether triol, 6.85 equivalents of tolylene diisocyanates,then 180 parts of this mixture is mixed with 3.7 parts of N, N, N,N'-tetrakis (2- hydroxy propyl) ethylene diamine, 15.5 parts of glycerolwith varying amounts of amine-type catalysts such as triethylene diamineand/or N-ethyl morpholine and from 1 to 2 parts of an auxiliary blowingagent, CFC 1 A suitable vinyl plastisol for use in rotational casting askin in accordance with the above example is finished crash pad removedfrom the Other vinyl polymers may be used to form plastisols or powdersols, as for example, polyvinyl acetate, polyvinyl alcohol andchlorosulfonated polyethylene and various vinyl copolymers such as acopolymer of vinyl chloride and vinylidene chloride, as are well knownin the art. Various plasticizers such as oxidized soybean oil anddiethylene glycol may be used and various other ingredients may be addedto form films having desirable characteristics as is well known in theart.

Also, other thermoplastic molding powers such as the terpolymer ofacrylonitrile, butadiene and styrene may be used to form the skin.

The polyurethane suitable for use in forming the foam may be thereaction product of an organic polyisocyanate and a polyester, apolyether polyol or a polyhydrocarbon polyol with or without the use ofan auxiliary blowing agent such as the low boiling materials, forinstance, fluorinated hydrocarbons and/or water.

Although the apparatus shown in FIGS. 1 to 3 is shown with stationaryhorizontal molds, this apparatus is particularly desirable for pouringlarge articles having an integrate configuration where difficulty isexperienced in getting air entrapment or the foaming mixture spread inthe desired pattern within the mold. in this instance, the flexibilityof this apparatuspermits a tilting mold to be used. Thus, the degree oftilt of the mold can be used to facilitate the spreading of the foamablemixture throughout the mold cavity and to allow the escape of air as thefoaming mixture expands. Then when the foam is cured, the mold can bereturned to the horizontal position to permit the mold to be opened andclosed more readily, as well as to allow the foamed'article to bestripped from the mold and a new skin to be placed therein.

A preferred embodiment of the tilting mold is shown in FIG. 4 whereinthe retaining mold is hingeably mounted 25 on the mold carriage or stand26 and a hydraulic cylinder 27 is positioned in the stand at the otherend 28 of the mold to move the mold from the horizontal position 29 tothe tilt position 30 (shown in dotted outline) in response to thehydraulic fluid to the hydraulic cylinder 31 by lines 32 and 33. Also,by giving the track 3 an S'shape in the vertical plane it is possible tovary the height of the mixing or pouring head from the floor tomaintain. the desired distance from the mold to the pouring head andthereby minimize spattering as different types and shapes of foamedarticles are molded.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in this art that various changes and modlficatlons may be madetherein without departing from the spirit or scope of the invention.

What I claim is:

1. A molding apparatus comprising in combination, a mold support meanshaving molds positioned thereon, a mixing head for the foamingingredients which is connected by flexible means to the supply means forthe foaming ingredients, means to support the mixing head above the moldsupport and to permit the mixing head to move from one mold to the nextmold without regard to sequence to position the mixing head above themold in mold-filling relationship, the flexible means being suspendedconvolutely from an overhead trackway and movable back and forth in saidtrackway in response to the movement of the mixing head.

2. The apparatus of claim 1 wherein the means for suspension of themixing head is a track arranged in a curve approximating a U-shapearound the means for supplying the foaming ingredients.

3. The apparatus of claim 1 wherein the mold has a means for changingthe elevation at one end thereof.

2. The apparatus of claim 1 wherein the means for suspension of the mixing head is a track arranged in a curve approximating a U-shape around the means for supplying the foaming ingredients.
 3. The apparatus of claim 1 wherein the mold has a means for changing the elevation at one end thereof. 